What is presently on the line to pull low? In other words, do you need to add a voltage line with a 10K pull up resistor to give it something to pull low to start with? A VOM will tell you. N5ZUA ----- Original Message ----- From: Bryan D. Boyle To: Geoff Cc: app_rpt-users@ohnosec.org Sent: Wednesday, June 05, 2013 11:53 AM Subject: Re: [App_rpt-users] DMK URI to Motorola R100 cor high or low? -- On Jun 5, 2013, at 12:38, Geoff <w5omr@att.net> wrote: It -really- can't be this hard... The Service manual for the R100 is at http://www.repeater-builder.com/motorola/r100/uhf-r100-service-manual-688107... On page 58 is the output of Jaux I'm using pins 14 - gnd 15 - spk hi 16 - Mic hi 17 - Mic gnd 18 - PL monitor (active low) 19 - PTT (active low) Corresponding Pins on the DMX URI ~should~ be (I would think) URI R100 Jaux 1 PTT 19 PTT 8 COR 18(*) PL Monitor 24 Ain 15 Spk Hi 12 Aout 16 Mic Hi 13 gnd 17 Mic gnd 13 gnd 14 gnd So... when I plug it in, the R100 keys up, and running radio-tune-menu, nothing works. (* = I use COR for PL monitor, because my R100 uses DPL (DCS) and not CTCSS.) Thoughts? -Geoff/W5OMR (29655)